Methane produced from syngas

Methane and acetylene can be effectively produced from syngas (CO-H2) in non-thermal plasma conditions. Syngas-based production of methane is an exothermic process ... 

Methanol is an important multipurpose intermediate traditionally used for production of various chemicals [57], It is currently produced from syngas, which is industrially generated via catalytic steam or autothermal reforming of methane [13-15]. Figure 23.7 schematically illustrates commercial and alternative routes for methanol formation from methane. Despite the fact that syngas production and methanol synthesis are highly optimized processes, strong economic and environmental interests exist in direct oxidative conversion of methane to methanol. 

Synthetic Natural Gas. Another potentially very large appHcation of coal gasification is the production of synthetic natural gas (SNG). The syngas produced from coal gasification is shifted to produce a H2-to-CO ratio of approximately 3 to 1. The carbon dioxide produced during shifting is removed, and CO and H2 react to produce methane (CH, or SNG, and water in a methanation reactor. 

Carbon Dioxide Removal. Aside from contained carbon dioxide which is removed from syngas when absorbing hydrogen sulfide, the total carbon dioxide produced in the methanation system is removed by conventional absorption in a single-stage operation in which the volume of gas to be treated is minimum and the partial pressure of the carbon dioxide is maximum. 

At present, methanol is (besides methane) the only chemical that can be produced with 100% selectivity from syngas, and it therefore constitutes a unique starting material for purely syngas-based industrial chemicals. This new role for methanol is also assisted by the ease of transporting it from areas where it can be cheaply produced from low-cost natural gas, coal or renewable sources such as biomass. The rising ethylene cost has given impetus to research devoted to finding routes in which ethylene can be replaced by methanol. 

Synthesis gas produced from steam methane reforming has a H2/CO ratio of approximately 6 1, much higher than required for most applications. Table 2 [4] shows the H2/CO ratios required for major syngas-derived petrochemicals. From Table 2, the required H2/CO ratio is typically between 0 and 2. To produce lower H2/CO ratios, hydrogen can either be separated from the syngas product or CO2 can be recycled to the reformer. 

High temperature methanation is conducted to produce substitute natural gas from syngas, and the Topsoe MCR catalyst is reported to have stable activity up to a temperature of700 °C for this reaction (417). The literature indicates that this catalyst contains 22 wt% nickel on a stabilized alumina support, has a surface area of 50 w g in its fresh state, and a surface area of 30 m g in its used state (418,419). 

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